from datetime import datetime

def calculate_age(birthday):
    now = datetime.now()
    bday_split = birthday.split('-')
    bday_year = int(bday_split[0])
    bday_month = int(bday_split[1])
    bday_day = int(bday_split[2])


def main():
    birthday = input("Please enter your birthday in the format YYYY-MM-DD: ")
    age = calculate_age(birthday)
    print(f"Your age is {age} years.")